| // Copyright 2009 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // +build ignore |
| |
| // Generate a self-signed X.509 certificate for a TLS server. Outputs to |
| // 'cert.pem' and 'key.pem' and will overwrite existing files. |
| |
| package main |
| |
| import ( |
| "crypto/ecdsa" |
| "crypto/elliptic" |
| "crypto/rand" |
| "crypto/rsa" |
| "crypto/x509" |
| "crypto/x509/pkix" |
| "encoding/pem" |
| "flag" |
| "fmt" |
| "log" |
| "math/big" |
| "net" |
| "os" |
| "strings" |
| "time" |
| ) |
| |
| var ( |
| host = flag.String("host", "", "Comma-separated hostnames and IPs to generate a certificate for") |
| validFrom = flag.String("start-date", "", "Creation date formatted as Jan 1 15:04:05 2011") |
| validFor = flag.Duration("duration", 365*24*time.Hour, "Duration that certificate is valid for") |
| isCA = flag.Bool("ca", false, "whether this cert should be its own Certificate Authority") |
| rsaBits = flag.Int("rsa-bits", 2048, "Size of RSA key to generate. Ignored if --ecdsa-curve is set") |
| ecdsaCurve = flag.String("ecdsa-curve", "", "ECDSA curve to use to generate a key. Valid values are P224, P256, P384, P521") |
| ) |
| |
| func publicKey(priv interface{}) interface{} { |
| switch k := priv.(type) { |
| case *rsa.PrivateKey: |
| return &k.PublicKey |
| case *ecdsa.PrivateKey: |
| return &k.PublicKey |
| default: |
| return nil |
| } |
| } |
| |
| func pemBlockForKey(priv interface{}) *pem.Block { |
| switch k := priv.(type) { |
| case *rsa.PrivateKey: |
| return &pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(k)} |
| case *ecdsa.PrivateKey: |
| b, err := x509.MarshalECPrivateKey(k) |
| if err != nil { |
| fmt.Fprintf(os.Stderr, "Unable to marshal ECDSA private key: %v", err) |
| os.Exit(2) |
| } |
| return &pem.Block{Type: "EC PRIVATE KEY", Bytes: b} |
| default: |
| return nil |
| } |
| } |
| |
| func main() { |
| flag.Parse() |
| |
| if len(*host) == 0 { |
| log.Fatalf("Missing required --host parameter") |
| } |
| |
| var priv interface{} |
| var err error |
| switch *ecdsaCurve { |
| case "": |
| priv, err = rsa.GenerateKey(rand.Reader, *rsaBits) |
| case "P224": |
| priv, err = ecdsa.GenerateKey(elliptic.P224(), rand.Reader) |
| case "P256": |
| priv, err = ecdsa.GenerateKey(elliptic.P256(), rand.Reader) |
| case "P384": |
| priv, err = ecdsa.GenerateKey(elliptic.P384(), rand.Reader) |
| case "P521": |
| priv, err = ecdsa.GenerateKey(elliptic.P521(), rand.Reader) |
| default: |
| fmt.Fprintf(os.Stderr, "Unrecognized elliptic curve: %q", *ecdsaCurve) |
| os.Exit(1) |
| } |
| if err != nil { |
| log.Fatalf("failed to generate private key: %s", err) |
| } |
| |
| var notBefore time.Time |
| if len(*validFrom) == 0 { |
| notBefore = time.Now() |
| } else { |
| notBefore, err = time.Parse("Jan 2 15:04:05 2006", *validFrom) |
| if err != nil { |
| fmt.Fprintf(os.Stderr, "Failed to parse creation date: %s\n", err) |
| os.Exit(1) |
| } |
| } |
| |
| notAfter := notBefore.Add(*validFor) |
| |
| serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128) |
| serialNumber, err := rand.Int(rand.Reader, serialNumberLimit) |
| if err != nil { |
| log.Fatalf("failed to generate serial number: %s", err) |
| } |
| |
| template := x509.Certificate{ |
| SerialNumber: serialNumber, |
| Subject: pkix.Name{ |
| Organization: []string{"Acme Co"}, |
| }, |
| NotBefore: notBefore, |
| NotAfter: notAfter, |
| |
| KeyUsage: x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature, |
| ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth}, |
| BasicConstraintsValid: true, |
| } |
| |
| hosts := strings.Split(*host, ",") |
| for _, h := range hosts { |
| if ip := net.ParseIP(h); ip != nil { |
| template.IPAddresses = append(template.IPAddresses, ip) |
| } else { |
| template.DNSNames = append(template.DNSNames, h) |
| } |
| } |
| |
| if *isCA { |
| template.IsCA = true |
| template.KeyUsage |= x509.KeyUsageCertSign |
| } |
| |
| derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, publicKey(priv), priv) |
| if err != nil { |
| log.Fatalf("Failed to create certificate: %s", err) |
| } |
| |
| certOut, err := os.Create("cert.pem") |
| if err != nil { |
| log.Fatalf("failed to open cert.pem for writing: %s", err) |
| } |
| pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes}) |
| certOut.Close() |
| log.Print("written cert.pem\n") |
| |
| keyOut, err := os.OpenFile("key.pem", os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600) |
| if err != nil { |
| log.Print("failed to open key.pem for writing:", err) |
| return |
| } |
| pem.Encode(keyOut, pemBlockForKey(priv)) |
| keyOut.Close() |
| log.Print("written key.pem\n") |
| } |